You are right that Batman blowing up the LOS temple at the beginning of BB--and I'd also add crashing his Batmobile head on to that first truck in TDK--in reality would have caused deaths. However, much like the comics, the explosions and fatalities indirectly caused by Batman in the background are glossed over. This is not unlike how Joker--in any medium--can seemingly smuggle explosives or Smilex gas into just about any place without concern be it a hospital, a ferry, a 1989 art museum, or a popular carnival from the mind of Frank Miller. Such logistics will always have to be overlooked.

As for the thematic "bankrupt" nature of TDKT? I will simply say that it is still to date the most intriguing and rich of its genre for conversations and critical thinking.

For example, you say that Batman straight up killed Talia Al Ghul. I would agree and consider it an evolution of his character:

In TDK, he is absolutist in his pathological need to save everyone. To the point where he would rather crash his motorcycle (and possibly kill himself) than stop the Joker from killing innocent civilians with lethal force. He even goes out of his way to save the Joker after throwing him off a skyscraper at the end. But when placed in a no-win scenario, he is forced to choose between saving Jim Gordon's son and stopping Harvey Dent in a process that would directly result in Dent's death. Whether you want to label this as murder or manslaughter, Batman killed Two-Face so Jim Gordon Jr. might live. He broke his one rule and that is why he is willing to create a cover-up for Harvey's crimes, if only to deprive Joker of his victory by stealing a pyrrhic one of his own.

In TDKR, Bruce is forced to confront all of his contradictions when he is left to rot as "a man of privilege" in a hole in the ground while his city burns. His obsession has consumed him to the point where he has no will to live beyond the mask, and he must give up that mask, as well as what some would deem the childish, or rather simplistic notions associated with it. To save Gotham, and just as importantly himself, he must put away his black-and-white worldview and the thought that he can save the world by playing by rules he more or less established for himself when he was in a place inconsolable rage and grief as a young man with a stunted worldview.

This is why he can:

1) Give up being Batman at the end.

2) Let Selina Kyle go, despite her sins.

3) Even appear in daylight at the end of TDKR as both a symbol AND a man, who is clearly flesh and blood in the sun's morning light. A first in the ENTIRE TRILOGY.

He has come out of the proverbial dark night and put away his "tricks and theatricality," as well as his tradition. It is why he also ignore his rules that he once broke for Dent without discrimination when his actions lead to the death of Talia and at least two of her minions (one driving the truck and at least one in a tumbler he leads missiles into). But he has "outgrown" Batman at this point, and has a more nuanced/utilitarian view of what "must be done."

The political implications of this is up to you. However, it is clearly not thematically bankrupt when we can even have this conversation.